Wonderful to have logging while leaning an engine and setting pitch ranges

That pretty much sums it up. It is SO nice to be able to monitor engine RPMs, throttle movements and head temperatures while leaning a engine out, setting pitch curves and fiddling with governor settings. Seeing the actual in-flight temps is SO much better than using a finger on the backplate or using an IR temp gun on the head 15 seconds after landing!

Here are three Eagle Tree Data Logger temperature graphs taken of break-in flights over the course of a week. With the logger and a netbook at the field, I was able to view the temp data on the ground and feel more confident about leaning the engine bit by bit. I otherwise would have been nervous - I had caused $150 in damage to an Align 91H from running it too lean earlier that month.

You can see by the end of the 3rd flying day I got my OS50 dialed in about as lean as I would probably want to go. Actually I've richened it a click or two since then for good measure - the difference in power and fuel economy are negligable but I like the extra insurance of a cooler engine.

Thanks! One thing to note is that my sensor is looped around the actual head and not the top of the crankcase throat recommended by some. That means that I'm measuring the hottest part of the engine and there is an expected temp increase at the end of each flight after the engine is shut down. If you can imagine, that removes the cool air source but it's OK because the piston isn't moving in the sleeve - what you're seeing is the latent combustion heat dissipating to the outside of the head. The main thing to look are the temperatures during flight. It's even cooler if you add a carb-smart because you can use the data logger to really dial in the ranges and to confirm it's working OK.

Would you like to share with us what changes to the spektrum sensor is required to get to work with ET?

Cheers
Jaco

Sure! Note that although this worked great for me, you should confirm the pinouts of your particular unit first - don't fry your logger by mistake!

The Spektrum sensor's output is a standard servo plug that plugs directly into the AR7100R (though you can also use it for other governors). The black wire is ground, red is power and white/yellow is signal.

Now, EagleTree decided to reverse the power and ground wires and you're not supposed to bridge power anyway, so the solution is this:

Confirm your governor is working fine and that it's sensing rotation with your starter spinning the motor. I'll presume you've already connected the logger to power either directly or off of a servo.

Turn everything off

Get a servo Y adapter with one female and two male ends

On one of the male ends (the one that will go to the logger), depress the flange and remove the red wire/pin and clip off the end because you don't want to bridge power

Push out the black wire/pin and re-insert it to where the red wire/pin used to go (remember, EagleTree reversed them on the RPM input)

Connect the adapter to your heli with the female going to the RPM sensor, the unmodified male to the governor (i.e. AR7100R) and the modified male to the logger

Testing time! Turn on your transmitter and receiver and make sure your data logger is powered up and isn't smoking . You may also want to clear its memory at this time. Rotate the fan to make sure your governor's sensor light activates or better yet, run your starter in the cup and make sure it's lighting up and (in live mode or downloading the data) the logger is sensing the rotation.

Of course you'll want to make sure you calibrate the sensor in the software with the right gear ratio (i.e. T600 is 8.5:1, Pantera 8.7:1) and tell it you're using a 1-pole magnet sensor. Also tell it you want to log RPM in the logger's memory.

Wow I have used the logger a few weeks now, and its really great to KNOW the numbers, and not just guessing it.
My temp-sensor was dead on arrival, so another two weeks without that, but I got some nice info about my electronics setup

For example:

I have futaba 9262 on cyclic, 9256 on tail. I measured about 380mAh from each tank, which is 8minutes and 30 seconds! Not bad!

Now I had great success with chinese weights on my 450 model, so I fitted some on my 600 tail grips aswell.
The current draw on each tank now, is under 200mAh!

This is somewhat fun, because I couldnt infact notice any difference when I was flying, but the numbers prove, there was a significant change there!

Now I just received my new temp-sensor, the hook and loop. But I have no idea how to attach it to my engine I am afraid to bust this one, as the last one seemed pretty fragile.

The mainshaft is very hard to get right with the optical sensor. FYI, Spektrum's magnetic crankcase sensor works great with a slight cable change ;-)

Can I use Spectrum's magnetic crankcase sensor directly with ET or do I need to do the mod that You mentioned in Your earlier post?
If I got it right, modification to spectrum sensor has to be done, even that I do not use the governor...

This is a great post. I am going buy one for sure…I have been shy about tuning my OS 105, and YS 120 for fear of overheating them and causing big bucks in damage. I am very surprised how high the temperatures clime when the engine shuts off. It sure takes the guess work out of tuning.thanks